Despite the recent interest in adopting HTML5's video tag, there is still one major problem: there is no mandated standard video codec for the video tag. The two main contestants are the proprietary and patended h264, and the open and free Theora. In a comment on an LWN.net article about this problematic situation, LWN reader Trelane posted an email exchange he had with MPEG-LA, which should further cement Theora as the obvious choice.

Agreed. Momentum should push the web to standards that anyone can implement. Websites are what they are today because the images and text is free. You can display it to the users without worrying whether their browser is able to display jpeg or PNG. I fear the same cannot be said about the video tag unless the landscape drastically changes.